linux-kernel - Re: [tip:irq/genirq] genirq: assert that irq handlers are indeed running in hardirq context

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Date:	Fri, 10 Apr 2009 15:11:43 +0800
From:	Eric Miao <eric.y.miao@...il.com>
To:	mingo@...hat.com, hpa@...or.com, linux-kernel@...r.kernel.org,
	a.p.zijlstra@...llo.nl, akpm@...ux-foundation.org,
	tglx@...utronix.de, mingo@...e.hu
Cc:	linux-tip-commits@...r.kernel.org
Subject: Re: [tip:irq/genirq] genirq: assert that irq handlers are indeed 
	running in hardirq context

On Tue, Mar 3, 2009 at 7:15 AM, Peter Zijlstra <a.p.zijlstra@...llo.nl> wrote:
> Commit-ID:  044d408409cc4e1bc75c886e27ca85c270db104c
> Gitweb:     http://git.kernel.org/tip/044d408409cc4e1bc75c886e27ca85c270db104c
> Author:     Peter Zijlstra <a.p.zijlstra@...llo.nl>
> AuthorDate: Mon, 2 Mar 2009 16:13:32 +0100
> Commit:     Ingo Molnar <mingo@...e.hu>
> CommitDate: Tue, 3 Mar 2009 00:05:45 +0100
>
> genirq: assert that irq handlers are indeed running in hardirq context
>
> Make sure the genirq layer handlers are indeed running handlers
> in hardirq context. That is the genirq expectation and doing
> anything else is broken.
>
> Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
> Cc: Andrew Morton <akpm@...ux-foundation.org>
> LKML-Reference: <1236006812.5330.632.camel@...top>
> Signed-off-by: Ingo Molnar <mingo@...e.hu>
>

OK, now this gave me the warning below and it looks resend_irqs()
and resend_tasklet are somehow found guilty and doing wrong, as
the comment of this commit suggested, yet I'm not sure if this makes
sense:


[   34.728943] ------------[ cut here ]------------
[   34.733573] WARNING: at
/home/ycmiao/work/linux-2.6/kernel/irq/handle.c:366
handle_IRQ_event+0x48/0x160()
[   34.743088] BUG: IRQ[82] handler called from non-hardirq
context!Modules linked in:
[   34.750729] [<c002e958>] (unwind_backtrace+0x0/0xdc) from
[<c00438d0>] (warn_slowpath+0x68/0x8c)
[   34.759520] [<c00438d0>] (warn_slowpath+0x68/0x8c) from
[<c006d100>] (handle_IRQ_event+0x48/0x160)
[   34.768461] [<c006d100>] (handle_IRQ_event+0x48/0x160) from
[<c006eb8c>] (handle_edge_irq+0x14c/0x1c4)
[   34.777747] [<c006eb8c>] (handle_edge_irq+0x14c/0x1c4) from
[<c006e440>] (resend_irqs+0x44/0x78)
[   34.786517] [<c006e440>] (resend_irqs+0x44/0x78) from [<c0048658>]
(tasklet_action+0x7c/0xdc)
[   34.795039] [<c0048658>] (tasklet_action+0x7c/0xdc) from
[<c0048b18>] (__do_softirq+0x60/0xe8)
[   34.803638] [<c0048b18>] (__do_softirq+0x60/0xe8) from [<c0048c88>]
(do_softirq+0x44/0x60)
[   34.811881] [<c0048c88>] (do_softirq+0x44/0x60) from [<c0048d1c>]
(ksoftirqd+0x78/0x168)
[   34.819953] [<c0048d1c>] (ksoftirqd+0x78/0x168) from [<c0058d38>]
(kthread+0x54/0x80)
[   34.827786] [<c0058d38>] (kthread+0x54/0x80) from [<c0046780>]
(do_exit+0x0/0x658)
[   34.835342] [<c0046780>] (do_exit+0x0/0x658) from [<00000000>] (0x0)
[   34.841687] ---[ end trace 26b21608484430d3 ]---



>
> ---
>  kernel/irq/handle.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
> index 3aba8d1..a2ee682 100644
> --- a/kernel/irq/handle.c
> +++ b/kernel/irq/handle.c
> @@ -328,6 +328,8 @@ irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
>        irqreturn_t ret, retval = IRQ_NONE;
>        unsigned int status = 0;
>
> +       WARN_ONCE(!in_irq(), "BUG: IRQ handler called from non-hardirq context!");
> +
>        if (!(action->flags & IRQF_DISABLED))
>                local_irq_enable_in_hardirq();
>
> --
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-- 
Cheers
- eric
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